DE-U-89 07 459 discloses an insertion rod for shaping upholstery materials covered externally in the case of upholstered furniture and similar upholstered seat components. This rod is a one-piece extruded shaping rod made of a plastic to which is rigidly connected a separately produced sew-on tag for its bonding to the cover material. The shaping rod has a two-sided shaping profile. The two sides are joined at their base by a narrow connecting strip, and delimit a mounting slot extending from this strip for the sew-on tag. The tag is rigidly bonded to the adjoining interior surface of the two profile sides.
To apply the disclosed solution, the insertion rod as profile component and the sew-on tag are bonded in a process in which the plastic materials of profile component and sew-on tag are melted and joined together by pressing. In the disclosed bonding processes, melting of the plastic materials results in damage, especially in the transitional area between the bonding seam and the adjoining plastic material of the components to be bonded, reducing the tear resistance. If thermal peaks occur during the bonding process, the danger exists that the bonding seam itself may be directly damaged. In addition, the known bonding processes require application of additional bonding heat to produce the bond, so that machinery and energy expenditures are increased in the disclosed processes, something which correspondingly increases manufacturing costs. The disadvantages could also be encountered if, in addition to the disclosed process specified for the German utility model, the bonding were to be effected by introduction of an additional material. This additional material has not been disclosed directly in connection with this utility model.
EP 1 060 092 B1 discloses another fastening system for a passenger seat having an upholstery element of a foam material enclosed in at least one upholstery cover component connected to a shaping strip serving as interlocking means as profile component and having interlocking elements on the exterior circumference. A longitudinal channel is adapted to the shape of the respective shaping strip in the foam upholstery element. The longitudinal channel in the upholstery element has recesses in the longitudinal direction serving the purpose of engagement of the interlocking elements of the profile component, ending in the longitudinal channel and being in the form of grooves. The disclosed shaping strip is configured as profile component as a semicircular rod, and thus, has a convex contact surface on its side facing the foam. On its opposite side, the shaping strip is configured to be level and is provided in its center with a slot-like seating channel as mounting opening for the sew-on tag to which in turn the upholstery cover component is fastened.
To produce this disclosed means of fastening, the sew-on tag may in turn be bonded to the shaping strip as profile component as described above. The foregoing or the respective bond is effected by adhesive means. A specially adapted plastic adhesive is readily obtainable on the market effecting the strong bond required. Since such adhesives are generally very expensive to produce, they make production of the fastening system more expensive. If the adhesive is configured as a two-component system, it must first be allowed to set properly for production of the strong bond, lengthening the production time required and accordingly increasing the cost. Since a large number of the plastic adhesives currently used contain solvents, evaporation of the solvent results in embrittlement of the areas to which adhesive is applied. Failure of the glued seam, and thus, of the point of bonding of the shaping strip and the sew-on tag may occur during the effective service life, at least in the long term. Adhesives containing solvents are not recommended for reasons of protecting the environment, in that they make subsequent recycling of seats and seat parts more difficult.